TOP100-4 Datasheet, PDF (7/20 Pages) Power Integrations, Inc. – Three-terminal Off-line PWM Switch

TOP100-4
L2
20 mH
BR1
200 V
C1
27 µF
200 V
VR1
P6KE91
D1
UF4004
D2
UG8BT
L1
3.3 µH
C2
680 µF
25 V
R1
39 Ω
R2
68 Ω
U2
NEC2501
VR2
1N5234B
6.2 V
D3
1N4148
C3
120 µF
25 V
7.5 V
RTN
C6
0.1 µF
F1
3.15 A
L
N
J1
DRAIN
SOURCE
CONTROL
U1
TOP101YAI
C5
47µF T1
10 V
C4
0.1 µF
CIRCUIT PERFORMANCE:
C7 Line Regulation - ±0.5%
1 nF
(85-132 VAC)
Y1 Load Regulation - ±1%
(10-100%)
Ripple Voltage ±50 mV
Meets CISPR-22 Class B
PI-1692-112895
Figure 8. Schematic Diagram of a 15 W 100/110 VAC Input Power Supply Utilizing the TOP101 and Simple Optocoupler Feedback.
Simple Optocoupler Feedback
The circuit shown in Figure 8 is a 7.5 V,
15 W secondary regulated flyback power
supply using the TOP101 that will
operate from 85 to 132 VAC input
voltage. Improved output voltage
accuracy and regulation over the circuit
of Figure 7 is achieved by using an
optocoupler and secondary referenced
Zener diode. The general operation of
the power stage of this circuit is the same
as that described for Figure 7.
The input voltage is rectified and filtered
by BR1 and C1. L2, C6 and C7 reduce
conducted emission currents. The bias
winding is rectified and filtered by D3
and C4 to create a typical 11 V bias
voltage. Zener diode (VR2) voltage
together with the forward voltage of the
LED in the optocoupler U2 determine
the output voltage. R1, the optocoupler
current transfer ratio, and the TOPSwitch
control current to duty cycle transfer
function set the DC control loop gain.
C5 together with the control pin dynamic
impedance and capacitor ESR establish
a control loop pole-zero pair. C5 also
determines the auto-restart frequency
and filters internal gate drive switching
currents. R2 and VR2 provide minimum
current loading when output current is
low. See DN-11 for more information
regarding low-cost, 15 W power
supplies.
Accurate Optocoupler Feedback
The circuit shown in Figure 9 is a highly
accurate, 15 V, 30 W secondary-
regulated flyback power supply that will
operate from 85 to 132 VAC input
voltage. A TL431 shunt regulator
directly senses and accurately regulates
the output voltage. The effective output
voltage can be fine tuned by adjusting
the resistor divider formed by R4 and
R5. Other output voltages are possible
by adjusting the transformer turns ratios
as well as the divider ratio.
The general operation of the input and
power stages of this circuit are the same
as that described for Figures 7 and 8. R3
and C5 tailor frequency response. The
TL431 (U3) regulates the output voltage
by controlling optocoupler LED current
(and TOPSwitch duty cycle) to maintain
an average voltage of 2.5 V at the TL431
input pin. Divider R4 and R5 determine
the actual output voltage. C9 rolls off
the high frequency gain of the TL431 for
stable operation. R1 limits optocoupler
LED current and determines high
frequency loop gain. For more
information, refer to application note
AN-14.
7 ^E
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